Implantable neurostimulation systems have proven therapeutic in a wide variety of diseases and disorders. Pacemakers and Implantable Cardiac Defibrillators (ICDs) have proven highly effective in the treatment of a number of cardiac conditions (e.g., arrhythmias). Spinal Cord Stimulation (SCS) systems have long been accepted as a therapeutic modality for the treatment of chronic pain syndromes, and the application of tissue stimulation has begun to expand to additional applications such as angina pectoralis and incontinence. Deep Brain Stimulation (DBS) has also been applied therapeutically for well over a decade for the treatment of refractory chronic pain syndromes, and DBS has also recently been applied in additional areas such as movement disorders and epilepsy. Further, in recent investigations Peripheral Nerve Stimulation (PNS) systems have demonstrated efficacy in the treatment of chronic pain syndromes and incontinence, and a number of additional applications are currently under investigation. Also, Functional Electrical Stimulation (FES) systems such as the Freehand system by NeuroControl (Cleveland, Ohio) have been applied to restore some functionality to paralyzed extremities in spinal cord injury patients.
These implantable neurostimulation systems typically include one or more electrode carrying neurostimulation leads, which are implanted at the desired stimulation site, and a neurostimulator (e.g., an implantable pulse generator (IPG)) implanted remotely from the stimulation site, but coupled either directly to the neurostimulation lead(s) or indirectly to the neurostimulation lead(s) via a lead extension. Thus, electrical pulses can be delivered from the neurostimulator to the neurostimulation leads to stimulate the tissue and provide the desired efficacious therapy to the patient. The neurostimulation system may further comprise a handheld patient programmer in the form of a remote control (RC) to remotely instruct the neurostimulator to generate electrical stimulation pulses in accordance with selected stimulation parameters. The RC may, itself, be programmed by a clinician, for example, by using a clinician's programmer (CP), which typically includes a general purpose computer, such as a laptop, with a programming software package installed thereon.
In the context of an SCS procedure, one or more neurostimulation leads are introduced through the patient's back into the epidural space, such that the electrodes carried by the leads are arranged in a desired pattern and spacing to create an electrode array. Multi-lead configurations have been increasingly used in electrical stimulation applications (e.g., neurostimulation, cardiac resynchronization therapy, etc.). In the neurostimulation application of SCS, the use of multiple leads increases the stimulation area and penetration depth (therefore coverage), as well as enables more combinations of anodic and cathodic electrodes for stimulation, such as transverse multipolar (bipolar, tripolar, or quadra-polar) stimulation, in addition to any longitudinal single lead configuration. After proper placement of the neurostimulation leads at the target area of the spinal cord, the leads are anchored in place at an exit site to prevent movement of the neurostimulation leads. To facilitate the location of the neurostimulator away from the exit point of the neurostimulation leads, lead extensions are sometimes used.
The neurostimulation leads, or the lead extensions, are then connected to the IPG, which can then be operated to generate electrical pulses that are delivered, through the electrodes, to the targeted tissue, and in particular, the dorsal column and dorsal root fibers within the spinal cord. The stimulation creates the sensation known as paresthesia, which can be characterized as an alternative sensation that replaces the pain signals sensed by the patient.
The efficacy of SCS is related to the ability to stimulate the spinal cord tissue corresponding to evoked paresthesia in the region of the body where the patient experiences pain. Thus, the working clinical paradigm is that achievement of an effective result from SCS depends on the neurostimulation lead or leads being placed in a location (both longitudinal and lateral) relative to the spinal tissue such that the electrical stimulation will induce paresthesia located in approximately the same place in the patient's body as the pain (i.e., the target of treatment). If a lead is not correctly positioned, it is possible that the patient will receive little or no benefit from an implanted SCS system. Thus, correct lead placement can mean the difference between effective and ineffective pain therapy.
As such, the CP (described briefly above) may be used to instruct the neurostimulator to apply electrical stimulation to test placement of the leads and/or electrodes inter-operatively (i.e., in the context of an operating room (OR) mapping procedure), thereby assuring that the leads and/or electrodes are implanted in effective locations within the patient. The patient may provide verbal feedback regarding the presence of paresthesia over the pain area, and based on this feedback, the lead positions may be adjusted and re-anchored if necessary. Any incisions are then closed to fully implant the system.
Post-operatively (i.e., after the surgical procedure has been completed), a fitting procedure, which may be referred to as a navigation session, may be performed using the CP to program the RC, and if applicable the IPG, with a set of stimulation parameters that best addresses the painful site, thereby optimizing or re-optimizing the therapy. Thus, the navigation session may be used to pinpoint the stimulation region or areas correlating to the pain. Such programming ability is particularly advantageous after implantation should the leads gradually or unexpectedly move, which if uncorrected, would relocate the paresthesia away from the pain site.
Typical programmable neurostimulation systems require a means to locate and navigate to a targeted implant location. For example, in the context of SCS, the CP may display graphical representations of the neurostimulation leads in relation to the spinal column of the patient, as described in U.S. Provisional Patent Application Ser. No. 61/390,112, entitled Neurostimulation System and Method with Anatomy and Physiology Driven Programming,” which is expressly incorporated herein by reference. Because it is desirable that the entire work area for an implant be displayed to medical personnel, current neurostimulation systems should display the entire spinal column, since neurostimulation leads can be implanted anywhere within the spinal column. However, because the size of a neurostimulation lead is much smaller than that of the spinal column, standard user interfaces are limited in that displaying the neurostimulation leads in the context of the entire spinal column may render any details of the neurostimulation leads and the immediately relevant region of the spinal column illegible.
There, thus, remains a need to provide a user interface capable of displaying an implant in the context of the entire work area while also displaying any details of the implant and the immediately surrounding portion of the work area in a legible manner.